Duff played one game in Major League Baseball, and in one at bat he didn't compile a hit.

Despite his limited playing time in the majors, Duff's minor league career spanned eight nonconsecutive seasons.

[3] In 1897, Duff began his professional career with the Class-B Fall River Indians of the New England League.

[4] On the season, Duff was tied for sixth in the league in home runs along with Thomas Ivers, and Bob Unglaub.

[4] In 1908, Duff played for the Class-B New Bedford Whalers, and the Lowell Tigers of the New England League.

In 13 games with the Class-D Norwich Bonbons/Meriden Doublins of the Connecticut Association, Duff batted .357 with 15 hits.